Originally Posted by Matt Trimmings

its mainly used with the closed cell foams, the air needs an escape route and it wont go through closed cell foams easily. Dont recommend it with standard foams. The hole is only roughly 1/16" so your not really ruining the tires.

Originally Posted by tonyd

Here is the reason!!!!
Tape the hole shut on the rims. I wish these companies would just stop putting holes in there wheels. All they do is let dust into your foams and they start to break down and get ruined.. With having a hole in the tire instead the dirt,dust and water from cleaning get flung out of the foam.
All foams need to breathe. If you don't put a hole in the tire after you tape the rim hole closed it will just bounce like a ball if air tight.

Originally Posted by Leadfinger2011

Water drainage and air release as some inserts need the air escape routes in order to function as designed.